Fluid leaks, particularly water leaks, in dwelling structures and commercial and industrial facilities account for a significant amount of structural damage and monetary losses on an annual basis. The causes of such leaks are varied and include faulty piping joints; old, worn-out or rusted piping; burst pipes due to temperature fluctuations; and so on. When such leaks occur, it is imperative to shut off the water (or other fluid) supply virtually immediately to prevent catastrophic damage from occurring. When dwelling residents or commercial or industrial facility employees are present, this may be readily accomplished once they perceive the existence of the leak. However, there are many situations in which dwelling residents, etc. are not present or otherwise not available to monitor the situation for an extended period of time (e.g., when they are on vacation, and overnight when occupants are asleep), and thus the existence of a leak may go unnoticed for a considerable period of time during which extensive damage can occur.
Obviously, the main water supply to homes and buildings cannot be turned off and on every time the occupants or employees plan to be away or retire for the evening. Thus, there has been a need for a system which automatically shuts off the flow of water (or other fluid) in a dwelling structure, commercial or industrial facility, responsive to the detection of a fluid leak in that system. A variety of attempts have been made to solve this problem. For example, the following U.S. patents each disclose a system or apparatus for shutting off water flow upon the sensing of a leak: Mallett U.S. Pat. No. 4,180,088; Meyer U.S. Pat. No. 4,518,955; Gordon et al. U.S. Pat. No. 4,845,472; White U.S. Pat. No. 5,056,554.
The systems and apparatus disclosed in the above-referenced patents tend to be quite complicated, some even incorporate computerized controls and/or complex flow sensing devices. For the most part, systems such as those disclosed are likely to be cost prohibitive and preclude installation in many homes, particularly mobile homes wherein substantial water damage occurs annually because the piping used in such homes tends to be more susceptible to leaking than the piping used in other dwelling structures or industrial facilities.
Thus, there continues to be a distinct need for an accurate, relatively compact, inexpensive and easy-to-install system for detecting leaks in a fluid system which automatically shuts off the fluid flow therein responsive to detection of a leak.